Poor service

My insurance booked a courtesy car for me on January with Avis Phalaborwa. I took back the car on 29th of January and was told to wait for the process of the refund. I called on the 24th of February to check the progress of my refund and took my information to do a follow up but I never got a feedback. I called again on the 18 and was told was told the supervisor was not in they will give a call after taking my details but i didn't receive any call and went to do a follow up again on the 20th of March but the same response that they will send my details as the refund is not processed by them in the Phalaborwa Branch.